Due to the advantages of light weight, thin thickness, small size, low power consumption, low heat, etc., an LCD (Liquid Crystal Display) stands out from numerous different types of displays and has been widely applied to TVs, computers, tablet computers, mobile phones and other modern information appliances.
For thin-film transistor liquid crystal display panels, the characteristics of the thin-film transistors have significant influence on the display quality of the display panels, and many poor display events are all related to the abnormity of characteristics of the thin-film transistors. For TN (Twirsted Enmatic) display panels, the switching characteristics of each thin-film transistor can be tested easily. However, for the conventional ADS (Advanced Super Dimension Switch) array substrates as shown in FIGS. 1A-1C, the switching characteristics of a thin-film transistor cannot be tested directly. As shown in FIGS. 1A-1C, a conventional ADS array substrate comprises a substrate 1; a gate 2 formed on the substrate 1; a gate insulating layer 7 formed on the gate 2; an active layer 4 being corresponding to the gate 2 and formed on the gate insulating layer 7; a source-drain electrode 3 formed on the active layer 4; a pixel electrode 5 formed on the gate insulating layer 7 and electrically connected to the drain of the thin-film transistor; a passivation layer 8 covering the source-drain electrode 3 and the pixel electrode 5; and a common electrode 6 being corresponding to the pixel electrode 5 and formed on the passivation layer 8. In the ADS array substrate, the pixel electrode 5 is located beneath the common electrode 6 and the passivation layer 8 (as shown in FIG. 1B and FIG. 1C), thus the switching characteristics of the thin-film transistor cannot be measured directly. As a result, it is unable to determine the impact of the characteristics of the thin-film transistor on the poor display events during failure analysis, greatly influencing the analysis for the poor display events of the display panel.